Adrian Moreno via dev <[email protected]> writes:

> Use the barrier trick to avoid clang from optimizing the 'size' variable
> that can cause the verifier to think that 'size' can be negative:
>
> ./upcall_monitor.py
> 119: (85) call bpf_probe_read_kernel#113
> R2 min value is negative, either use unsigned or 'var &= const'
> processed 131 insns (limit 1000000) max_states_per_insn 0 total_states
> peak_states 9 mark_read 3
> Traceback (most recent call last):
> File "/ovs/utilities/usdt-scripts/./upcall_monitor.py", line 729, in
> odule>
> main()
> File "/ovs/utilities/usdt-scripts/./upcall_monitor.py", line 697, in
> in
> b = BPF(text=source, usdt_contexts=usdt, debug=options.debug)
> File "/usr/lib/python3.9/site-packages/bcc/__init__.py", line 373, in
> init__
> self._trace_autoload()
> File "/usr/lib/python3.9/site-packages/bcc/__init__.py", line 1241, in
> race_autoload
> fn = self.load_func(func_name, BPF.KPROBE)
> File "/usr/lib/python3.9/site-packages/bcc/__init__.py", line 412, in
> ad_func
> raise Exception("Failed to load BPF program %s: %s" %
> Exception: Failed to load BPF program b'kretprobe__ovs_dp_upcall':
> permission denied.
>
> Signed-off-by: Adrian Moreno <[email protected]>
> ---

Looks fine to me, but I think it would be useful to include which kernel
version(s) you observed this issue with.  For example, was this on
RHEL9/Centos9?  Ubuntu 22.04?  Debian?  Kernel 4.18, 5.14, latest
upstream?

_______________________________________________
dev mailing list
[email protected]
https://mail.openvswitch.org/mailman/listinfo/ovs-dev

Reply via email to